It really depends.
Most saddles are in the $175-$250 range. After that it gets very subjective...
What kind of climbing method are you going to use? Multiple sticks? One-Stick? SRT? DRT? Then with each comes individual costs within? Do you want a platform? Use the top of a stick? Use a Ring of Steps? Or some kind of DIY?
I would say most spend $400-$500 on average. Some higher and some lower. It really depends on how much DIY you want and exactly what you want to do.
I am one-sticking so I have my saddle (250 for the Tethrd Phantom), my platform (170 Tethrd Predator), Hawk Helium 20" modded one-stick (100), 35ft of 9mm Oplux (70), repelling device (70), lineman belt (25), several carabiners (35), pack (40), miscellaneous things such as straps,
recliner band, foam cushions (50)
Now that me....someone else may be more DIY and cheaper, and the next person will have every gadget you could think of and sail past me.